An insulated gate bipolar transistor (IGBT) is a composite full-controlled voltage-driven power semiconductor device including a bipolar junction transistor (BJT) and an insulated-gate field-effect transistor. The insulated gate bipolar transistor has advantages of both high input impedance and low conduction voltage drop. Therefore, the insulated gate bipolar transistor, an important switching device, has been widely used in a variety of switching circuit structures. For example, the insulated gate bipolar transistor has been used in frequency converter, inverter, and other circuit structures.
However, the electrical performance of the conventional insulated gate bipolar transistor still needs to be improved. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems.